Update MD013/line-length to include strict mode (fixes #237).

doc/Rules.md

@@ -453,7 +453,7 @@ Tags: line_length
 
 Aliases: line-length
 
-Parameters: line_length, heading_line_length, code_block_line_length, code_blocks, tables, headings, headers (number; default 80, boolean; default true)
+Parameters: line_length, heading_line_length, code_block_line_length, code_blocks, tables, headings, headers, strict (number; default 80, boolean; default true)
 
 > If `headings` is not provided, `headers` (deprecated) will be used.
 
@@ -465,7 +465,8 @@ up into multiple lines. To set a different maximum length for headings, use
 
 This rule has an exception where there is no whitespace beyond the configured
 line length. This allows you to still include items such as long URLs without
-being forced to break them in the middle.
+being forced to break them in the middle. To disable this exception, set the
+`strict` parameter to `true`.
 
 You have the option to exclude this rule for code blocks, tables, or headings.
 To do so, set the `code_blocks`, `tables`, or `headings` parameter(s) to false.

helpers/helpers.js

@@ -385,12 +385,8 @@ module.exports.rangeFromRegExp = function rangeFromRegExp(line, regexp) {
   let range = null;
   const match = line.match(regexp);
   if (match) {
-    let column = match.index + 1;
-    let length = match[0].length;
-    if (match[2]) {
-      column += match[1].length;
-      length -= match[1].length;
-    }
+    const column = match.index + 1;
+    const length = match[0].length;
     range = [ column, length ];
   }
   return range;

lib/md013.js

@@ -3,11 +3,12 @@
 "use strict";
 
 const { addErrorDetailIf, filterTokens, forEachHeading, forEachLine,
-  includesSorted, rangeFromRegExp } = require("../helpers");
+  includesSorted } = require("../helpers");
 const { lineMetadata } = require("./cache");
 
-const longLineRePrefix = "^(.{";
-const longLineRePostfix = "})(.*\\s.*)$";
+const longLineRePrefix = "^.{";
+const longLineRePostfixRelaxed = "}.*\\s.*$";
+const longLineRePostfixStrict = "}.+$";
 const labelRe = /^\s*\[.*[^\\]]:/;
 const linkOnlyLineRe = /^[es]*lT?L[ES]*$/;
 const tokenTypeMap = {
@@ -28,6 +29,9 @@ module.exports = {
     const lineLength = params.config.line_length || 80;
     const headingLineLength = params.config.heading_line_length || lineLength;
     const codeLineLength = params.config.code_block_line_length || lineLength;
+    const strict = !!params.config.strict;
+    const longLineRePostfix =
+      strict ? longLineRePostfixStrict : longLineRePostfixRelaxed;
     const longLineRe =
       new RegExp(longLineRePrefix + lineLength + longLineRePostfix);
     const longHeadingLineRe =
@@ -71,11 +75,18 @@ module.exports = {
       if ((includeCodeBlocks || !inCode) &&
           (includeTables || !inTable) &&
           (includeHeadings || !isHeading) &&
-          !includesSorted(linkOnlyLineNumbers, lineNumber) &&
-          lengthRe.test(line) &&
-          !labelRe.test(line)) {
-        addErrorDetailIf(onError, lineNumber, length, line.length,
-          null, null, rangeFromRegExp(line, lengthRe));
+          (strict ||
+           (!includesSorted(linkOnlyLineNumbers, lineNumber) &&
+            !labelRe.test(line))) &&
+          lengthRe.test(line)) {
+        addErrorDetailIf(
+          onError,
+          lineNumber,
+          length,
+          line.length,
+          null,
+          null,
+          [ length + 1, line.length - length ]);
       }
     });
   }

schema/build-config-schema.js

@@ -171,6 +171,11 @@ rules.forEach(function forRule(rule) {
           "description": "Include headings",
           "type": "boolean",
           "default": true
+        },
+        "strict": {
+          "description": "Strict length checking",
+          "type": "boolean",
+          "default": false
         }
       };
       break;

schema/markdownlint-config-schema.json

@@ -418,6 +418,11 @@
           "description": "Include headings",
           "type": "boolean",
           "default": true
+        },
+        "strict": {
+          "description": "Strict length checking",
+          "type": "boolean",
+          "default": false
         }
       },
       "additionalProperties": false
@@ -464,6 +469,11 @@
           "description": "Include headings",
           "type": "boolean",
           "default": true
+        },
+        "strict": {
+          "description": "Strict length checking",
+          "type": "boolean",
+          "default": false
         }
       },
       "additionalProperties": false

test/long-lines-strict.json

@@ -0,0 +1,8 @@
+{
+  "default": true,
+  "MD013": {
+    "strict": true,
+    "heading_line_length": 30,
+    "code_block_line_length": 20
+  }
+}

test/long-lines-strict.md

@@ -0,0 +1,31 @@
+# Long Lines Strict
+
+12345678901234567890123456789012345678901234567890123456789012345678901234567890
+
+This line is too long. text text text text text text text text text text text text
+
+This line is way too long. text text text text text text text text text text text text
+
+This line is barely too long. text text text text text text text text text text t
+
+This line is just okay. text text text text text text text text text text text t
+
+This line is not a problem. text text text text text text text text text text t
+
+## This heading is way too long
+
+## This heading is long but ok
+
+## This heading is short + ok
+
+```text
+This code is too long
+This code is a-okay.
+This code is short.
+```
+
+{MD013:5}
+{MD013:7}
+{MD013:9}
+{MD013:15}
+{MD013:22}